What is the magic formula?

For the distance vertically from lift arm attach points to top link point on a 3 point implement. I just finished building a dirt plane and I looked at two three point implements in the yard to get the vertical distance. When I tested it the front wanted to dig too aggressively, and when I picked it up the back would not lift as high as the front. I studied it and decided to lower the lift arm attach points. After this adjustment it now works perfectly.

(quoted from post at 10:07:00 07/26/13) For the distance vertically from lift arm attach points to top link point on a 3 point implement. I just finished building a dirt plane and I looked at two three point implements in the yard to get the vertical distance. When I tested it the front wanted to dig too aggressively, and when I picked it up the back would not lift as high as the front. I studied it and decided to lower the lift arm attach points. After this adjustment it now works perfectly.

Click to expand...

ike diapers....it depends. CAT I, II, III? Or if tractor built before the standards came into existence, then it is whatever the N-tractor or other designers pulled out of the air.
Google ASAE S217.

A few around my yard:

Here you go. I made a mistake on the first posting and it's corrected in this one I think Click on the link to see the original posting

For those of you who like to build your own attachments.

Category 1 Specs on the machine.
Upper hitch point........inside width.....1.75" outside width..... max......2.75" hole diameter....3/4"

Lower .......pin dia. ...7/8" lower pin width.....26 3/4" Mast height pin center to pin center 18"
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Category 2 machine specs.
Upper Hitch point......inside width.......2" outside width.....max.....3"+ hole diameter.....1"

Lower.........pin dia. ...1 1/8" Lower pin width.....32 1/4" Mast height pin center to pin center .....18"
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Category 3 machine specs.
Upper hitch point......inside width........2"+ outside width... max......3 3/4" hole dia......1 1/4"

Lower........pin dia.....1 7/16" Lower pin width....38" Mast height pin center to pin center 22"
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Category 4 machine specs
Upper hitch point......inside width....____ lower pin width.... 46" Mast height..........._____

Lower pin dia.......2" Lower pin width.....46" Mast height pin center to pin center.......______

Category 0 specs on the machine
Upper hitch point ......inside width.....2" outside width.....2 3/4" hole diameter.....5/8"

Lower pin dia........5/8" lower pin width.....20" Mast height center to center......13 3/4"

Notice the blank spaces on category four no machines around here that big. Other dimensions taken from machines in the back yard and on a lot bigger place than mine. The lower pin width is the shoulder to shoulder width on the pins you use.
3 POINT HITCH SPECIFICATIONS

Dave;

That 26-3/4" for the lower pins is from center of pin hole to center of pin hole, correct?

Larry

The 26 3/4" dimension is for the drawbar the lift arms of the tractor hook to. It is not lynch pin hole to lynch pin hole, Example, on an eleven hole Ford drawbar it is the length of the drawbar without the round pin the lift arm balls go over.